This invention relates to inflatable plastic sheeting articles having multiple air compartments, such as, air mattresses, floats and the like, and particularly to those having reforming and reinforcing, inflatable units formed by additional outer sheets which are superimposed on and sealed to the main inflatable bodies thereof.
Inflatable articles, such as, air mattresses, floats, in the past, are made of two gas impervious sheets a and b which are joined together at their edges by heat sealing and provided with parallelly spaced apart longitudinally heat welded seams c in the area bounded by the edge seams to form adjacent air passages or compartments as shown in FIG. 1. This type of construction has less stiffness so that it has a tendency to deform or curve other than flat after inflation and also the sheeting at the seams is liable to tear. Furthermore, when it is inflated, it can not exhibit a neat configuration as the seam portions are apparently lower in position than other portions. One of the improvements is made by providing inner membranes e which are sealed to the inner sides of the two sheets for defining the air compartments as shown in FIG. 2. Nevertheless, the provision of such membranes may creates a complication in porcessing.
The manufacture of inflatable plastic sheeting articles having exteriorly formed inflatable portions superimposed on the inflatable main bodies are well known in the art. In U.S. Pat. No. 2,170,539, there is disclosed a toy ballon of irregular shape having sunken portions and projecting portions, the projecting portions being independently formed and superimposed on the main inflatable body of the toy ballon for providing an amount of rigidity of the projecting portions so that these portions can be retained in their desired shape. U.S. Pat. No. 1,851,768 discloses water toys which are provided with inflatable projecting portions at the lower parts thereof for floating the toys in the upright positions. In both patents, there is only disclosed inflatable projecting portions formed at certain parts on the wall of the main inflatable body. These projecting portions are not multiple-compartmented and are not necessarily formed at the edge portion or throughout the whole construction of the main inflatable body.